Call-registering system for automatic telephone systems



C. L. GOODRUM.

CALL REGISTERING SYSTEM FOR AUTOMATIC TELEPHONE SYSTEMS.

APPLZCATION HLED APR. 24. l9l5.

Patented Aug. 1, 1916.

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APPLICATION FILED APR. 24,1915.

Patented Aug. 1, 1916.

UNITED STATES PATENT OFFICE.

CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS,TO WESTERN ELECTRIC COMIPANY, INCORPORATED, A CORPORATION OF NEW YORK.

CALL-REGISTERING SYSTEM FOR AUTOMATIC TELEPHONE SYSTEMS.

Application filed April 24, 1915.

To all whom it may concern:

Be it known that I, CHARLES L. GooDRUM, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Call-RegisteringSystems for Automatic Telephone Systems, of which the following is afull, clear, concise, and exact description.

This invention relates to telephone exchange systems employing automaticline finderswitches for associating calling lines with idle connectingcircuits. Its object is to provide an improved metering circuitarrangement for such systems.

In accordance with this invention the operating magnet of the meter ofeach line is connected to the multiple test contacts of such line in theautomatic finder switches in which such line appears and is of lowresistance, and the test circuits of the finders are of high resistancerelative to that of the meter magnets. Vith this arrangement the metersare not operated during the testing operation of the finders, since thecircuit conditions are such that their operating magnets will notreceive enough current. When the calling line has been extended to aconnecting circuit, however, and connection has been made with thewanted line, the response of the called party renders operative meansfor closing a circuit of suilicient strength to operate the calling linemeter magnet. The meter magnet is provided with a locking winding sothat upon its actuation it will remain locked up during the entireduration of the connection and thus prevent accidental operation of themeter. This locking winding may be included in parallel with the cut-offrelay of the line and may be controlled at an off-normal contact of thefinder.

Referring to the drawingsFigures 1 and 2 show a circuit arrangementembodying the invention.

The subscribers lines a b terminate as calling lines in multiplecontacts 137, 138 of a group of finders like that shown diagrammaticallyin Fig. 1, and as called lines in multiple contacts 225, 226 of a groupof connectors like that shown diagrammatically in Fig. The closure ofthe line circuit by the removal of the receiver from its switchhook by acalling party causes an idle line fi der to be set in motion to connectwith Specification of Letters Patent.

Patented Aug. 1, 1916.

Serial No. 23,565.

such line. The finder then in a primary rotary movement, selects thegroup of terminals containing the calling line and in a secondaryvertical movement the particular line in such group which is calling.The calling line is thus extended to the connec tor shown in Fig. 2which is in turn caused to connect with the desired line by a primaryand secondary movement under the control of the sender 157 of thecalling party at substation A.

A general description of the mode of op eration having been given, it isthought the invention will be readily understood from a detaileddescription of the operation of interconnecting two substations.

The removal of the receiver 100 at sub station A causes the closure ofthe line circuit and the operation of the line relay 108. Relay 108 atits armature and front contact closes the circuit of relay 101 which iscommon to the group of subscribers to which substation A belongs. Therelay 101 at its armature and front contact closes the following circuitfor slow acting relay 105 to start the line finder in motion: free poleof battery, relay 105, conductors 102, 111, finder off-normal contact103, now closed to conduetor 111, conductors 104, 109, armature andfront contact of group relay 101, to ground. A circuit for theside-switch escapement magnet 107 in parallel with re lay 105 is alsoclosed by relay 101 as follows: free pole of battery, left-hand windingof escapement magnet 107, conductors 110, 111, finder off-normal contact103 to ground over the circuit just traced for relay 105. If the finderallotted to this group of lines is idle, a brush 115 carried by itswiper carrier or shaft (not shown) rests on a dead or home contact 116.In this posi tion a set of wipers 128, 133, 136, 139 ca.r ried by thefinder shaft is one step removed from operative relation to the group ofline terminals containing those of substation A. It is thereforenecessary to give the finder shaft one rotary step before it can huntover the terminals in the group to which it is allotted.

Upon the closure of the front contact of slow relay 105, due to theenergization of relay 101 as described, the following circuit is closedfor the primary stepping magnet 118 of the line finder to give thefinder this rotary step to pick out the group of lines containingcalling substation A: free pole of battery, primary stepping magnet 118,armature and back contact thereof, conductor 119, side-switch arm 120and its first contact, conductor 127, right-hand winding of escapementmagnet 107, conductor 122, righthand armature and front contact ofslowacting relay 105, conductor 123, conductor 200 (Fig. 2), left-handarmature and back contact of relay 201, conductor 202, righthandarmature and back contact of relay 203, conductor 204, armature and backcontact of relay 205 to ground. The primary stepping magnet 118thereupon interrupts this circuit at its front contact and a pawlcarried thereby (not shown), rotates the finder brush shaft one step,whereupon the group test brush 115 engages the segment 158 of the groupcontaining substation A, from which ground was removed at the backcontact of the group relay 101. Side-switch escapement magnet 107releases the side or steering switch into its second position in thewellknown manner, due to the opening of offnormal contact 103. While thecircuit of relay 105 is also opened when finder offnormal contact 103opens, it is slow acting and before it can release its armatures thefollowing circuit is closed through its right hand armature and frontcontact free pole of battery, conductor 125, secondary stepping magnet106, its armature and back contact, conductor 126, side-switch arm 120and its second contact, conductor 127, righthand winding of side-switchescapement magnet 1 07, conductor 122, right-hand armature and frontcontact of slow relay 105, conductor 123, conductor 200 to ground at theback contact of relay 205 over the circuit previously traced. Thesecondary stepping magnet 106, by means of a pawl (not shown) connectedto its armature gives the shaft of the line finder a secondary verticalstep due to the closure of this circuit, whereupon its brushes 139, 136,133, 128, engage with the first set of terminals of the group containingthe terminals 138, 137, 132, 129 of calling line A. Contact betweenbrush 128 and test terminal 129 occurs beforethe armature of magnet 106opens its back contact, this opening occurring near the end of itsstroke. Escapement magnet 107 attracts its armature due to the closureof this circuit and locks itself up to ground at the armatures andbackcontacts of the line relays 108 of non-calling lines over the followingcircuit: freepole of battery left-hand high resistance winding ofescapement magnet 107, armature and front contact of said magnet,conductor 112, side-switch arm 113 and its second contact, conductor161, brush 128, terminals 129, low resistance right-hand windings ofmeter magnets 143, conductors 147, to ground at the armatures and backcontacts of line relays 108. This circuit is closed before slow relay105 releases. This relay is therefore maintained energized in parallelwith escapement magnet 107. The secondary stepping magnet 106 nowinterrupts its circuit and causes the line finder brushes to wipe overthe terminals of the calling group. This circuit is as follows: freepoleof battery, a conductor 125, magnet 106, its armature and backcontact, conductor 126, side-switch arm 120 and its second contact,conductor 127, right-hand winding of escapement magnet 107, conductor122, right-hand armature and front Contact of slow relay 105, conductor123 to ground at the back contact of relay 205 of the connector over thecircuit previously traced. As soon as the calling line is reached, theescapement magnet 107 and slow relay 105 are deenergized, since noground is present on the test terminal 129 thereof, due to theenergization of the line relay 108. The escapement magnet 107 thereuponreleases the side switch into position 3. The meter magnets 143 of thelines passed over during this testing operation do not receivesufficient current to operate them, due to the high resistance of theright-hand winding of escapement magnet 107. When the side switch movesinto position 3, cutoff relay 130 is immediately operated over thefollowing circuit: free pole of battery, relay 130, conductor 131,contact 132, brush 133, conductor 134, side-switch arm 113 and its thirdcontact, conductor 112, armature and back contact of escapement magnet107 to ground. The ground placed on brush 133 at the back contact ofescapement magnet 107 causes this line to test busy in the connectors inwhich this line appears as will hereinafter appear.

The cutoff relay 1'30 upon operating causes the deenergization of linerelay 108 which, at its armature and back contact, restores this line tonon-calling condition by grounding its multiple test contacts 129. Asthe side switch moves into position 3, relay 205' at the connector isenergized over the following circuit: free pole of battery, lefthandwinding of relay 205, conductor 206, arm 207 and first contact of theconnector side-switch, conductor 132, polarized relay 133, side-switcharm 134 and its third contact, conductor 135, finder brush 136, contact137', line conductor 1), the telephone set of substation A. lineconductor a, contact 138, finder brush 139, conductor 140, side switcharm 141 and its third contact, con ductor 142, conductor 208 side-switcharm 209 and its first contact, conductor 210, right-hand winding ofrelay 205 to ground.

The relay 133 is polarized so as not to operate by the closure of thecircuit for relay-205 just traced. Relay 205, upon its energization,closes a circuit for slow acting relay 203 at its armature and frontcontact.

Relay 203, at its right-hand armature and front contact, prepares acircuit for the pri mary stepping magnet 227. The calling subscriber nowoperates his sender 157 and interrupts the circuit of relay 205 a numberof times, corresponding to the tens digit of the number of the calledline. Each time the armature of relay 205 closes its back contact acircuit for primary stepping magnet 227 is closed as follows: free poleof battery, magnet 227, side-switch arm 228, conductors 229, 212,right-hand arn'iature and front contact of slow relay 203, conductor201-, armature and back contact of relay 205, to ground. The magnet 22?thus moves the wiper shaft in a primary direction by a pawl and ratchet(not shown), to pick out the group in the connector to which the calledline belongs. Upon the first break in the line circuit and theconsequent falling back of the armature of relay 205, a circuit wasclosed for the sideswitch escapement magnet 231 of the conncctor asfollows: free pole of battery, magnet 231, conductor 21 2, armature andfront contact of relay 203, conductor 201, armature and back contact ofrelay 205 to ground. This magnet being slow-acting, remains energizeduntil the closure of the line circuit at the end of the tens series ofbrwaks. whereupon it falls back and moves the side switch into position2 in the wellknown manner. Arm 22S thereof, in position 2 prepares acircuit for the secondary magnet Upon the operation of the sender 157 intransmitting the units digit of the wanted number, relay 203 isintermittently deiinergized and the secondary stepping magnet moves theconnector brushes to the terminals of the wanted line, the circuit beingas follows: free pole of battery, magnet 232, side-switch arm 228 andits second contact. coinlnctors 229, 212, right-hand armature and frontcontact of slow relay 203. conductor 204', armature and back contact ofrelay 205 to ground, it being understood that slow acting relay 203remains energized as during the first series of line circuitinterruptions. Escapement magnet 231 was energized upon the firstclosure of the back contact of the armature of relay 205 as during thetens selecting o 'ieration, and being slowacting, releases only when theseries of interruptions of the line circuit corresponding to the unitsdigit is over. It is then deenergized and moves the side switch intoposition 3. The selected line is inn'nediately made to test busy in theconnectors in which it appears by sideswitch arm 233 grounding themultiple test contacts 23s thereof, and the cut-off relay of the calledline corresponding to relay 130 of Fig. 1 is operated.

In position 3. the arm 228 of the side switch closes a circuit for theescapement magnet 231 to close the ringing circuit. This circuit is asfollows: free pole of battery, magnet 231, conductor 229, arm 223 andits third contact, conductors 235, 217, armature and back contact ofringing control relay 2.18, to ground. The escapcment magnet at itsright-hand armature and front contact closes the ringing circuit asfollows: free pole of ringing generator 236, ringing control relay 213,conductor 237, right-hand armature and front contact of escapementmagnet 231, conductor 23S, side switch arm 23$) and its third contact,conductor 210, brush 211, terminal 226, line conductor a, bell 212. lineconductor 0, terminal 225, brush 213, conductor 211, arm 215, conductor216, conductor 221, arn'iature and front contact of relay 205, toground. \Vhen the called party answers, the marginal relay 218 isenergized and opens the circuit of the escapement magnet 231, whereuponthe cscapcmcnt magnet releases the side switch into position 1, thusopening the ringing circuit. Relay 201 is now energized and talkingcurrent is supplied to the called line through the windings of thisrelay. It will be noted that when the side switch moves into position 4:upon the response of the called party, arms 207-, 200 of the side switchreverse the connection of the battery supplied to the calling party. Thepolarized relay 133 thereupon operates.

Upon the operation of polarized relay 133, it closes at its armature andfront contact a circuit of sufficient strength to energize the metermagnet 143. This circuit is as follows: free pole of battery (Fig. 1),primary stepping magnet 118, conductor 144, armature and front contactof polarized relay 133, conductors 115, 161, brush 128, contact 120,conductor 11 6, right-hand winding of meter magnet 11?), conductor 117.right-hand armature and back contact of line relay 108 to ground. Theoperation of magnet 113 has no ellect at this time. The Ineter magnetthereupon attracts its armature 118. The armature of meter magnet 143carries the stepping pawl 110 of the meter which. by advancing ratchetwheel 151 a step. records the connection which has just been built up.Armature 113 at its front contact closes a locking circuit for the metermagnet as follows: free pole of battery. left-hand winding of the metermagnet 113, conductor 150, armature 11S, and front contact of the metermagnet, conductor 152, conductor 131, contact 132, brush 133. conductor13f. side switch arm 113 and its third contact, armature and backcontact of escapement magnet 10? to ground. Thus the meter remainslocked until the connection is disestablished to prevent the accidentaloperation of the meter.

\Yhen the subscribers hang up their re" rcivers upon the conclusimi ofthe Quin yersation, the relays 205 and 201 at the connector are deinergized. The following circuit for the release magnet 153 of the finderis thereupon closed: free pole of battery, release magnet 153, tinderoff-normal contact 134', conductor 155, right-hand armature and backcontact of slow relay 105, conductor 123, conductor 200 (Fig. 2),lefthand armature and back contact of relay 201, conductor 202,right-hand armature and back contact of relay 203, conductor 201-,armature and back contact of relay 205 to ground. In case the callingsubscriber hangs up his receiver before the called sub scriber, therelease circuit is the same as that previously traced up to theleft-hand armature of relay 201, and from thence passes by way of frontcontact of said armature, conductors 211 and 212, right-hand armatureand front contact of relay 203, which is slow to release its armature,conductor 201, armature and back contact of relay 205 to ground. Thisimpulse is sufficient to energize release magnet 153, which thereuponattracts its armature and locks itself up to ground through the finderoff-normal contact 1.31 until the finder completely restores, whereuponit is decnergizcd by the opening of such otf-nbrlnal contact.

When the called subscriber hangs up his recciyer, the circuit forrelease magnet 213 of the connector is closed as follows: free pole ofbattery, lett hand winding of release magnet 213, conductor 214,right-hand armature and back contact of relay 201, conductor 21-3,sideswitch arm 210 and its fourth contact, conductor 217, armature andback contact of the ringing control rclay 21b, to ground. The releasemagnet 2133, upon its energization, restores the side switch to itsnormal position and closes a locking circuit for itself as follows: freepole of battery, lclthand winding of re lease magnet 21 conductor 211,right-hand armature and back contact of relay 201. conductor 215.side-switch arm 2'10 and its third. s cond or first contact, conductor220, connector switch olf-norn1al contact 221, conductor 222. left-handarmature and back contact of relay 20 i, conductor 223, conductor 217,lefthand armature and back contact of relay 201, conductor 202,right-hand armature and back contact of relay 203, conductor 20 t,armature and back contact of relay 205, to ground.

If the called subscriber hangs up his receiver before the callingsubscriber the circuit previously traced for release magnet 213 throughits left-hand winding to ground at the armature and back contact ofringing control relay 218 is closed whereupon the release magnet at itsleft-hand armature and front contact locks itself over the followingcircuit: free pole of battery, right-hand winding of release 2123, itsleft-hand armature and front contact, conductors 219, 224, 218, toground at the armature and front contact of relay 205.

In case the wanted line is busy as a called line its test terminal 23-1is grounded by side-switch arm of another connector; if busy as acalling line, said test terminal is grounded by side-switch arm 113 andarmature and back contact of escapement magnet 107 of another finder. inthis event, when under the control of the sender 1 of the calling party,the connector selects such busy line, the connector is immediatelyreleased and a busy signal is given to the calling party. lt will berecalled that when the line circuit is permanently closed at the end ofthe last or units series of interruptions, the escapement magnet 2231 ofthe side switch of the connector is deciiergized and releases the sideswitch into position I to signal the selected line. lts left-handarmature is so arranged, however, that it closes its back contact beforethe side switch is released. The following circuit is then closed forrelease magnet 213 of the connector, if ground is present on testterminal 231 of the selected line, which will be the use if the line isbusy as just explained: free pole of battery, left-hand winding ofrelease magnet 213, conductor 21st, right-hand armature and back contactof relay 201, conductor 215, side-switch arm 210 and its second contact,conductor 220, connector off-normal contact 221, conductor 222,left-hand armature and back contact of slo\\-acting escapcl'nent magnet231, 0011- ductor 219, side-switch arni 233 and its second contact,conductor 250, brush 251, contact 231, to ground either at theside-switch arm and its third or fourth contact of the connectorconnected to a multiple con tact of this line, or at the back contact ofthe escapement magnet 10? of a tinder connected to a multiple contact ofthis line. Thus the connector is rel usual. The release magnet 213 atits left-hand armature and front contact locks itself over the followingcircuit: free pole of battery, right-hand locking winding, left-handarmature and front contact conductors 210. 221, 218, armature and frontcontact of relay 205 to ground. The release nnwnet 213 at its right-handarmature and front contact ap plies a busy tone over conductors 252, 253to the calling line.

\Vhen the calling party hangs up his receiver, relay 205 isdeenergiaaed, opening at its armature and front contact the lockingcircuit of magnet 213, and at its back contact closing the followingcircuit to release the finder: ground, armature and back contact ofrelay 205, conductor 204. right-hand armature and back contact of relay203, conductor 202, left-hand arn'iature and back contact of relay 201,conductors 2 17, 200,

123, armature and back contact of relay 105, conductor 155, off-normalcontact 15 1, release magnet 153 to free pole of battery. The releasemagnet locks itself up as previously described until the finder hasreached its normal position, when by the opening of off-normal contact154, it is released.

The finders are allotted to the calling lines by an extended starterwire. Each line group has a finder whose contact brush 115 normallyrests on a home segment 116 of such group, adjacent a. segment 158, alsoindividual to such group. Thus, if a call comes in from any line in thegroup to which it is allotted, a single rotary step only of the brushshaft of the finder of such group is necessary to position its brushesto wipe over the terminals of such group as has just been shown. If thefinder shown in Fig. 1 had been busy when the call just traced wasinitiated, the starter wire 104 would have been extended by finderoff-nor- 11ml contact 103, bottom, to the next idle finder, which wouldfirst be given a primary rotary movement by means of its primarystepping magnet corresponding to 118 of Fig. 1 to place such finder in aposition to move its brushes over the terminals of the group containingthe calling line. The starting circuit for such finder would then be asfollows: ground, right-hand armature and front contact of group relay101, conductors 109, 101, off-norn'ial contact 103 bottom, conductor180, armature and back contact of slow relay 105, conductor 159 to theprimary magnet of the next idle finder. From this point the operationmay be traced by reference to Fig. 1, and assuming the finder showntherein to be the idle one. The circuit then continues by conductors160, 10$). to escapement magnet 107 and slow relay 105, from which pointthe operation is the same as that already traced, except that theside-switch escapement magnet 107 of such finder would lock itself up tothe grounded segments 158 of the non-calling line groups. and thusmaintain the stepping circuit of the primary magnet 118 of such finderclosed until the brush 115 thereof reaches the segment 158 of thecalling line group from which ground is removed. Magnet 10? thereuponreleases the side switch into position 2 to open the circuit of suchprimary stepping magnet and close the circuit of the secondary steppingmagnet 100 of such finder to move the wipers over the calling group.From this point on, the operation is the, same as that alreadydescribed.

lVhile in the present embodiment of the invention, the meter is operatedupon the response of the called party, it is within the scope of theinvention to operate the meter at some other stage in the process ofbuilding up or disestablishing the connection.

\Vhen the invention is applied to semi-automatic systems the polarizedrelay 133 may be under the control of the operator at the centralofiice. For simplicity, no intermediate selectors have been shown. It isobvious however, that in actual practice a number of such selectorswould be interposed between the finder shown in Fig. 1 and the connectorof Fig. 2 depending upon the size of the exchange.

What is claimed is:

1. In a telephone exchange system, the combination with telephone lines,automatic fin-der switches wherein said lines terminate in multiplecontacts, multiple test contacts for said lines in said finders, ofmeters connected with said test contacts and each provided with anoperating winding of low resistance, a high resistance test circuitassociated with each of said finders, an operating circuit for saidmeter magnets associated with each of said finders, and means operatedupon the response of the called party for closing said operating circuitto actuate the calling line meter.

2. In a telephone exchange system, the combination with telephone lines,automatic finder switches wherein said lines terminate in multiplecontacts, multiple test contacts for said lines in said finders, ofmeters connected with said test contacts and each provided with anoperating winding of low resistance, a test circuit associated with eachof said finders including a test relay of relatively high resistance, anoperating circuit for said meter magnets associated with each of saidfinders, and means operated upon the response of the called party forclosing said operating circuit to actuate the calling line meter.

In a. telephone exchange system, the combimition with telephone lines,means for interconnecting the same including auto matic finder switcheswherein said lines terminate in multiple contacts, multiple testterminals for said lines in said finders, of meters for said linesconnected to said test terminals and provided with a double wound magnethaving an operating winding of low resistance and a locking winding, ahigh resistance test circuit for each of said finders, an operatingcircuit for said meter magnets associated with each of said finders, andmeans actuated upon the response of the called party for closing saidoperating circuit to actuate the calling line meter, whereupon saidmeter magnet locks itself up by means of its locking winding.

4. In a telephone exchange system, the combination with telephone lines,means for interconnecting the same including automatic finder switcheswherein said lines terminate in multiple contacts, multiple testterminals for said lines in said finders, of meters for said linesconnected to said test terminals and provided with an operating magnetof low resistance, a test circuit for each of said finders including atest relay of relatively high resistance, an operating circuit for saidmeter magnets associated with each of said finders and a polarized relayoperated upon the response of the called party for closing saidoperating circuit to actuate the calling line meter.

5. In a telephone exchange system, the combination with telephone lines,means for interconnecting the same including automatic finder switcheswherein said lines terminate in multiple contacts, multiple testterminals for said lines in said finders, of meters for said linesconnected to said test terminals and provided with an operating magnetof low resistance, a test circuit for each of said finders includingsaid meter magnet and a test relay of relatively high resistance, and anoperating circuit for said meter magnets associated with each of saidfinders.

(3. In a telephone exchange system, the combination With telephonelines, finder switches wherein said lines terminate, normally-groundedmultiple test contacts for said lines in said finders, a line relay foreach line adapted when operated to remove ground from its multiple testcontacts, steering switches for said finders, high resistance escapementmagnets therefor, a test circuit for each finder including itsescapement magnet, means for causing one of said finders to wipe oversaid test contacts and for energizing its escapement magnet upon theoperation of any of said line relays, circuits for maintaining saidmagnet energized including grounded non-calling line test contacts,whereby when the test brush reaches the non-grmmded calling line testcontact said magnet is decnergizei'l to move the associated steeringswitch to open the finder driving circuit, means operated by thestopping of the finder for replacing ground upon the calling line testterminals, :1 low resistance meter magnet for each line connected to itsmultiple test contacts, and means operated upon the response of thecalled party for closing an operating circuit for the talling line metermagnet.

In witness whereof, I hereunto subscribe my name this 2] st day ofApril, A. D. 1915.

CHARLES L. GOODRUM.

copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D, C.

